The issue has been resolved by disabling the specific rule system wide. This will not impact protection as multiple black lists are used and the non-commercial version is used alongside the commercial service from the same provider. A new rule pointing to the commercial service will be reintroduced and enabled by default. We apologise for the inconvenience and obvious concern this will have caused whilst we analysed the issue. Protection – and the accuracy of that protection – has not been affected


Engineers have identified the underlying cause of the issue to a non-commercial black list provider that has introduced a lookup limit which is causing intermittent failures. This black list has now been disabled.


We are currently investigating an issue where a small number of inbound emails are sometimes being blocked by the IP reputation rules. Engineers are currently investigating, and we will update this page with further information when available.

Began at:

Affected components
  • Email Security
    • Europe
    • North America